The invention concerns a method for the preparation of a dry textile preform for a large surface area component, in particular with a spherically curved surface, and a device for the execution of such a method.
A method and a device for the preparation of a dry textile preform for a spherically shaped component are, for example, shown in the patent application DE 10 2006 021 110 A1 of the applicant. Dry, i.e. resin-free carbon fibre entities are stored in the rolled-up state on each of two reels. For the laying down of the fibre entities onto a moulding body the rolled-up fibre entities are individually positioned over the moulding body and lowered, wherein during the lowering they are unrolled by means of opposing movements of the reels in horizontal directions. After the laying down of a fibre entity the moulding body is rotated about its vertical axis through a certain angle and a further fibre entity is laid down on the moulding body, or onto the preceding fibre entity. This method is repeated until the preform has a certain number of fibre entities and thus a certain number of layers. The preform is then fed through to a resin infiltration process and an autoclave process for purposes of curing.
By virtue of the automated laying down of the fibre entities labour-intensive manual procedures for draping the fibre entities on the moulding body are dispensed with in this method. However, the preparation of the fibre entities on each of the two reels is relatively labour-intensive, since the fibre entities must be rolled up and unrolled under a constant tension in order to prevent folds, creases and similar in the fibre entities, the removal of which would require manual corrective measures. The formation of folds, creases and similar during the rolling up procedure can be reduced, amongst other measures, by ensuring that the fibre entities have a constant length over their whole cross-section, since then the fibre entities can be laid down on the rollers with step-free leading and trailing edges. However, depending on the cross-sectional shape of the component that is to be produced, the fibre entities often have sections of different lengths for purposes of minimising the material waste. For example, fibre entities for a round component cross-section often have side sections that are shortened relative to a central section, so that a step-shaped leading and trailing edge is formed. For purposes of equalising the section lengths the side sections are then lengthened to the length of the central section by means of textile pieces that are fastened on, for example, glass fibre mats, which after the laying down on the moulding body are then removed once again. The fastening on of the textile pieces is, however, in particular very time-intensive. Moreover the reels are very heavy, and for purposes of driving and manipulation thus require correspondingly high-power drives and heavy-duty bearings.